CONTROL MICROSYSTEMS Thermocouple Analog Input Module. Hardware Manual

Transcription

1 550 Thermocouple Analog Input Hardware Manual CONTROL MICROSYSTEMS SCADA products... for the distance Steacie Drive Telephone: Kanata, Ontario Facsimile: KK A9 Technical Support: Canada -CONTROL

2 Control Microsystems Inc. All rights reserved. Printed in Canada. Trademarks TeleSAFE, TelePACE, SmartWIRE, SCADAPack, TeleSAFE Micro6 and TeleBUS are registered trademarks of Control Microsystems Inc. All other product names are copyright and registered trademarks or trade names of their respective owners. Material used in the User and Reference manual section titled SCADAServer OLE Automation Reference is distributed under license from the OPC Foundation.

3 Table of Contents OVERVIEW... 3 IMPORTANT SAFETY INFORMATION... 3 INSTALLATION Environment Considerations Field Wiring Address Selection Thermocouple Range Selection... 7 OPERATION AND MAINTENANCE Data Format Fail-Safe Conditions Cold Junction Compensation Linearization Maintenance Troubleshooting Calibration SPECIFICATIONS... 6 APPROVALS AND CERTIFICATIONS... Index of Figures Figure : Typical 550 Thermocouple Field Wiring... 6 Figure : 550 Thermocouple Input Address Switches... 7 Figure 3: 550 Thermocouple Range Switches...

4 Overview The Model 550 Thermocouple input module adds eight thermocouple inputs to the 5000 Series input/output system. Up to eight model 550 modules may be connected to the I/O bus, for a total of 6 thermocouple inputs per bus. The 550 module can be used with J, K, E and T type thermocouples or 0 to 0 millivolt input signals. The 550 module provides an iso-thermal block for maintaining the thermocouple termination wiring at a know temperature. The temperature of this block is monitored to provide cold junction compensation. The 550 module uses a 0000 count, integrating, analog to digital (A/D) converter. A single chip microcontroller with integral watchdog timer operates the A/D, linearizes and scales the output data and communicates over the I/O bus. All inputs are transient protected and optically isolated from the main logic power. 3

5 Important Safety Information Power, input and output (i/o) wiring must be in accordance with Class I, Division wiring methods Article 50- (b) of the National Electrical Code, NFPA 70 for installations in the U.S., or as specified in Section -J of the Canadian Electrical Code for installations within Canada and in accordance with the authority having jurisdiction. WARNING! EXPLOSION HAZARD - SUBSTITUTION OF COMPONENTS MAY IMPAIR SUITABILITY FOR CLASS, DIVISION. WARNING! EXPLOSION HAZARD WHEN IN HAZARDOUS LOCATIONS, TURN OFF POWER BEFORE REPLACING OR WIRING MODULES. WARNING! EXPLOSION HAZARD - DO NOT DISCONNECT EQUIPMENT UNLESS POWER HAS BEEN SWITCHED OFF OR THE AREA IS KNOWN TO BE NONHAZARDOUS.

6 3 Installation The installation of the 550 module requires mounting the module on the 7.5mm by 35mm DIN rail and connecting the module to the system I/O Bus. Refer to the System Configuration Guide, at the beginning of this manual, for complete information on system layout, I/O Bus cable routing and module installation. 3.. Environment Considerations The 550 module cold junction compensation circuitry must not be subjected to rapid temperature changes. These can occur when a cabinet door is opened. Install 550 modules in a manner, which will eliminate, or at least minimize, the possibility of rapid temperature changes. 3. Field Wiring The 550 module provides eight thermocouple inputs. Figure : Typical 550 Thermocouple Field Wiring shows how to wire the inputs. An external volt supply powers the isolated input circuits. A 5000 Series power supply normally sources this voltage. A range of voltages can be tolerated. Refer to section 5-Specifications for details. If an isolated V-power supply is used, such as a 5000 Series 503 power supply, it is necessary to reference this supply to chassis ground. This connection to chassis may be built into another device being powered from the V power supply but is most easily accomplished by connecting the V of one of the 550 modules to the nearest DIN rail chassis ground. If it is necessary to have the thermocouples at a potential other than chassis ground this chassis connection can be made through a high value resistor. Screw termination style connectors are used for termination of field wiring. They accommodate solid or stranded wires from to AWG. The connectors are fixed to the circuit board and are not removable. CAUTION: To remove the connector: Remove power before servicing unit. Pull the connector upward from the board. Apply even pressure to both ends of the connector. To install the connector: Line up the pins on the module with the holes in the connector. Make sure all the pins line up properly. Push the connector onto the pins. Apply even pressure to both ends on the connector. 5

7 Volt Input P P V Supply T/C 0 T/C T/C T/C 3 T/C T/C 5 T/C 6 T/C 7 See Field Wiring section regarding chassis ground connection. Figure : Typical 550 Thermocouple Field Wiring 3.3 Address Selection The 5000 Series I/O bus will support a maximum of forty I/O (input/output) modules Series I/O module types may be combined in any manner to the maximum supported by the controller used. The types of input and output modules available are: Digital Input modules Digital Output modules Analog Input modules Analog Output modules Counter Input modules Each type of I/O module, connected to the I/O bus, must have a unique I/O module address. Different types of I/O modules may have the same module address. The address range supported by the SmartWIRE, SCADAPack or TeleSAFE Micro6 controller module may restrict the I/O module address range. Refer to the controller manual for the maximum address supported. The three address switches labeled,, and set the module address. To set the address: Open all three switches by pressing down the left side of the switch. Close the switches that total to the desired address. Figure : 550 Thermocouple Input Address Switches shows the switch settings for all 6 possible module addresses. 6

8 How to Set Switches Determine the module address. Press the side of the switches shown in gray above. Press this side to ignore switch value Press this side to add switch value Figure : 550 Thermocouple Input Address Switches 3. Thermocouple Range Selection The 550 module scales and linearizes input readings depending on the thermocouple range selected. These ranges are summarized in the table below. Figure 3: 550 Thermocouple Range Switches below shows the switch settings for the 5 possible ranges. Input Type Range Resolution at 0ºC J 00 to 760ºC 0.0ºC 0 K 70 to 370ºC 0.0ºC E 70 to 000ºC 0.07ºC T 70 to 00ºC 0.0ºC 3 Voltage 0 to 0 mv µv Select Range The resolution shown above is typical of the resolution over most of the range for temperatures above 0ºC. Thermocouples are very non-linear, especially at temperatures below 00ºC. 7

9 Range 0 J type Range K type Range E type Range 3 T type Range ±0mV How to Set Range Switches Determine the desired range. Press the side of the switches shown in gray above. Figure 3: 550 Thermocouple Range Switches

10 Operation and Maintenance. Data Format 5000 Series analog input and output modules use 6 bit signed numbers (5 bits plus sign). The 550 module has a 0000 count, bipolar, analog to digital (A/D) converter. All of the thermocouple ranges use a fraction of the A/D range. The readings are scaled and linearized to provide output data in the 6 bit signed format. The table below shows output values for several temperature inputs based on the J type thermocouple range. Temperature Conditio n Output < 00ºC operating 63 00ºC operating 63 0ºC operating 0 0.0ºC operating 3 00ºC operating 3 30ºC operating ºC operating ºC operating 3767 NA open 3767 input NA +V off 0. Fail-Safe Conditions The 550 module output data has two special conditions. If the thermocouple is open the data goes to full scale (3767). If the V power supply is off the data goes to 0..3 Cold Junction Compensation When the thermocouple wiring is terminated on a terminal block a second thermocouple is created. Cold junction compensation is necessary to eliminate the effects of this cold junction thermocouple. The terminal block of the 550 module is connected a large mass (iso-thermal block). The cold junction sensor measures the temperature of this block. The 550 module compensates the thermocouple readings for temperature variations at the terminal block. The cold junction compensation circuit must not be subjected to rapid temperature changes, for the circuit to function properly. These can occur when a cabinet door is opened. Install 550 modules in a manner, which will eliminate, or at least minimize, the possibility of rapid temperature changes.. Linearization The 550 module scales and linearizes the output data for the thermocouple range selected. Linearization is accomplished by dividing the temperature vs. voltage curve into approximately 0 segments and extrapolating to generate an output that is a function of temperature. 9

11 Some thermocouples become extremely non-linear at temperatures below 00ºC. The low temperature limit on the accuracy specification reflects this limitation of the thermocouple. Range Temperature Linearization Errors J 00 to 760ºC +0.03% K 30 to 370ºC +0.03% E 0 to 000ºC +0.03% T 0 to 00ºC +0.03% ±0mV NA NA.5 Maintenance This module requires no routine maintenance. If the module is not functioning correctly, contact Control Microsystems Technical Support for more information and instructions for returning the module for repair..6 Troubleshooting Problem Inputs always read 0. Inputs always read Reading is constant. Action Check +V power. Check the range switches. Check for open input. Check the range switches. Check that the analog input is not forced..7 Calibration The 550 module is calibrated and burned in at the factory. It does not require periodic calibration. Calibration may be necessary if the module has been repaired as a result of damage. There is one potentiometer for calibration of the analog inputs. The GAIN potentiometer (R) adjusts the gain. Calibration requires that you read the converted value from the module using a communication controller, SCADAPack or TeleSAFE Micro6 controller module. Refer to the controller module manual for details. To calibrate the module:. Set the range switches to range (±0mV).. Short any one of the analog inputs. 3. Adjust the ZERO potentiometer until a reading of 0 is obtained.. Apply a stable voltage between 70 and 0 mv on any one of the analog inputs. 5. Calculate the correct reading for the applied voltage using the formula: voltage reading 376 0mV 6. Adjust the GAIN potentiometer until the correct reading is obtained. 0

12 The calibration may be verified by applying other voltages or voltages of the opposite polarity to the other input terminals. Use the formula above to determine the correct reading for each input voltage.

13 5 Specifications Disclaimer: Control Microsystems reserves the right to change product specifications without notice. For more information visit Inputs Thermocouple Types and Ranges Resolution Input Resistance Accuracy over 0 o C to 60 o C operating temperature range thermocouples or millivolt signals Type J 00 to 760ºC Type K 70 to 370ºC Type E 70 to 000ºC Type T 70 to 00ºC mv ±0mV 0.00 mv approximately 0.0 o C refer to section 3.-Thermocouple Range Selection. M Type J ±0.0% of full scale Type K ±0.0% of full scale Type E ±0.5% of full scale Type T ±0.50% of full scale mv ±0.5% of full scale Cold Junction Compensation Converter type Common mode voltage range Isolation Transient Protection Response Time Power Requirements Terminations Dimensions Mounting Packaging All figures include linearization errors, but not cold junction compensation errors. Errors at operating temperatures from 0 o C to 50 o C are typically one-half those stated above. Accuracy decreases at measured temperatures below 00ºC. Refer to section.-linearization for details. ±0.5ºC maximum error from 0 to 60ºC ±ºC maximum error from 0 to 0ºC ±0000 count, integrating ±0V can be applied to the inputs, relative to the V power supply input. 500 VAC from the logic power MOVs on each input 0.5 seconds 5V at 0mA 0 to V at 5mA 0 pole and pole two fixed terminal blocks to AWG 5 amp contacts 5.65 inch ( mm) wide.65 inch ( mm) high.75 inch ( mm) deep 7.5 x 35 DIN rail corrosion resistant zinc plated steel with black enamel paint

14 Environment 5% RH to 95% RH, non-condensing 0 o C to 60 o C 0 o F to 0 o F 3

15 6 Approvals and Certifications Safety Non-Incendive Electrical Equipment for Use in Class I, Division Groups A, B, C and D Hazardous Locations.